going to use braided line for the first time on my new casting setup. I have 10 pound mono that i have not used. It is stren so not the best of quality, will this line work for backing in my spool? also i plan on tieing direct, will this be okay with jigs crankbaits etc?

That mono will work fine for backing. I like to fill at least 1/4 of the spool. 

You certainly can direct tie to about anything without to many issues. You might want to use a leader for clear water and abrasion resistance. But many people forgo the leader altogether. I direct tie most of the time myself.

that line will be fine for backing and i almost always tie direct so no worries there either.

What knot do you plan on using for the mono-to-braid connection?

10# mono is perfect for backing, not too thick so it's hard to manage, not to thin where you need to spool a lot.  As thebillsman pointed out make sure you use a secure knot between your mono-to-braid.

That will be fine for backing. In clear water you might want to add a leader depending on what you're doing. You might also want to add a mono leader if you're throwing walking topwaters that have treble hooks as braid has a tendency to tangle in the front hooks.